This puzzle asks you to find the single category linking five clues: Earth, The Sun, Marbles, Soap bubbles (when free floating), and Basketballs (but not rugby balls). The answer is Things that are spherical. Each clue is a concrete example of a broader collection. The answer is the set label that every row belongs to without stretching the meaning. With only "Earth", many categories could fit. Hold your first guess and watch what clue 2 eliminates. "Earth" and "The Sun" must share one repeatable link — not a coincidence between two words. By clue 3 ("Marbles"), "Things that are spherical" should explain all three without bending meanings. "Soap bubbles (when free floating)" strengthens "Things that are spherical" rather than opening a new theory. The final clue ("Basketballs (but not rugby balls)") confirms "Things that are spherical" — if it still fits naturally, the category is locked. Use the Solution tab above for an interactive clue-by-clue walkthrough, or the Solved board tab for the complete answer at a glance.